Figure 4.

Time course analysis of the inhibitory effects of calcitriol on chemokine secretion in tumour necrosis factor alpha (TNFα)/interferon gamma (IFNγ)-treated airway smooth muscle (ASM) cells. Cells were stimulated for 24 h with TNFα (10 ng mL⁻¹) and IFNγ (500 IU mL⁻¹), and 100 nM of calcitriol was added either 1 h before, simultaneously, or 6, 12 and 18 h after cytokine treatment. Secretion of RANTES (a) and fractalkine (FKN) (b) was analysed as described under Materials and methods. Values shown are mean±s.e.mean of three separate experiments. ^*P<0.05 compared with cells treated with TNFα/IFNγ; ^**P<0.01 compared with cells treated with TNFα and IFNγ.